2-Hydroxy isobutyric acid

Kemp and Waters found a primary kinetic isotope effect of 8.7 for oxidation of C-deuterated mandelic acid and noted a large difference in rate between the oxidations of mandelic acid k at 24.4 °C = 1.7 l.mole . sec ) and a-hydroxy-isobutyric acid ( 2 at 24.4 °C = 5.6 x 10 l.mole . sec ) — a difference not reproduced for the oxidation of these compounds by the one-equivalent reagent, manganic sulphate. The various data are fully in accord with a Westheimer-type mechanism, viz. 

Hydroxy-isobutyric acid 2 Captopril Treatment for hypertension Hydroxylation Candida rugosa Single-stage fermentation [4]... 

Escambia (1) A process for oxidizing isobutene to a-hydroxy-isobutyric acid (HIBA), for use as an intermediate in the manufacture of methacrylates. The oxidant was dinitrogen tetroxide, N204. Operated by the Escambia Chemical Corporation, FL, in 1965 before its destruction by an explosion in 1967. It has not been used again. 

BA, SA Dried roast beef, sugared fruit, mixed with aqueous a-hydroxy-isobutyric acid solution (pH 4.5) and HTA, sonicated/ A/residue washed with aceto-nitrile-H20 (2 3, v/v), /B/, A and B combined Sep-Pak Cl8, 5 yam Acetonitrile-50 mM aqueous a-hydroxy-isobutyric acid (pH 4.5) (2.2 3.4 or 2.4 3.6, v/v) containing 2.5 mM HTA UV 233 nm 81... 

The use of 8-hydroxy isobutyric acid (pH 4.6, 0.4 M) as the eluting agent should be more advantagous, rather than the elution using citric acid.(43). 

As the eluting agent, the use of B-hydroxy Isobutyric acid should be more advantageous (43). 

The product nuclei from the target are collected on thin Au foils. These foils are dissolved and the hulk of the fission product and Induced radioactivity are removed ty a combination of solvent-extraction and Ion exchange techniques. The actinide fraction Is separated into the components by rapid elution from Dowex-50 cation-exchange resin, with Cf-hydroxy isobutyric acid as the eluant (42). 

Complex formation is useful for metal speciation and also for the separation of diverse metal ions. Among a variety of complexing reagents [20-22] cyanide is probably the most important. IPC separation of metal ions as metallocyanide complexes with a suitable cationic IPR is a reliable technique [23]. Complexation of trace level lanthanides with a-hydroxy isobutyric acid and separation under IPC condition shortened analysis time from days to minutes [24]. Flow injection was successfully coupled to IPC to simplify batch precomplexation detection limits were at sub-microgram per liter levels [2]. 

The analogous reaction with a ketone is illustrated from the work of Staedeler in 1859, who prepared a-hydroxy-isobutyric acid from acetone, hydrocyanic acid and hydrochloric acid, without isolating the intermediate acetone cyanohydrin. 

A new technique was used that allowed the atoms of Md to recoil from the very thin target onto a "catcher" foil. Thirteen atoms of Md (ti 1.3 h) were made in 9 h of irradiation and isolated by rapid elution from a colunm of cation exchange resin using a solution of of-hydroxy isobutyric acid. The elution showed 5 atoms of element 101 (identified by the spontaneous fission of the daughter f m) and 8 atoms of the Fm daughter (Fig. 16.7 eqn. (16.10)). The recoil — ion exchange technique used in... 

After irradiation the sample was dissolved in hydrochloric acid. A known amount of all the lanthanides (0.5-1 mg. each) and 10 mg. of barium were added, the cerium was oxidized and subsequently reduced to ensure complete exchange of carrier and cerium activity, and the lanthanides were separated and purified as a group using a series of fiuoride and hydroxide precipitations. The final hydroxide precipitate was dissolved in dilute hydrochloric acid and adsorbed to 80 mg. of Dowex 50. The resin was transferred to the top of an ion exchange column (Dowex 50X12, NH4 -form, settling rate 0.5-1.5 cm./min.), and the lanthanides were eluted using a-hydroxy-isobutyric acid and continu-... 

In rats and mice exposed to MTBE, unchanged MTBE and tert-butyl alcohol were shown to be the main respiratory excretion products. MTBE has also been found to be metabolized to formaldehyde, methanol, formic acid, carbon dioxide, 2-methyl-1,2-propanediol, and a-hydroxy-isobutyric acid. MTBE has not been shown to bioaccumulate in the tissues (ATSDR, 1996). 

The final products of metabolism in animals are carbon dioxide, methanol, and a-hydroxy-isobutyric acid. The toxicities of these products should also be considered. 

The apparent failure of moulds to metabolize a-hydroxy-isobutyric acid has led to the suggestion that this acid might be useful for buffers (pH 2.3—5.0) a table is available (Tobie and Ayres, 1945). 

Ethyl-3-hydroxy- Mean 3 0.8 6.6 3.9 - 3-Hydroxy-isobutyric acid-... 

Ar-O (4 1) atmosphere separation with naphthenic-HCl system Extraction chromatographic separation with bis (2-ethyIhexyl) phosphate on ECieselgulir Li-chromosorb cation exchanger, 2-hydroxy isobutyric acid... 

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